Esters of organic carboxylic acids



Patented Feb. 16, 1954 ESTERS OF ORGANIC CARBOXYLIC ACIDS Quentin E. Thompson,

Monsanto Chemical Louis, Mo., assignor to Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application December 7, 1951, Serial No. 260,566

12 Claims.

This invention relates to optically active 4, 4a,- 5,8-tetrahydro 2 alkoxy 4a methyl-4-oxo-lnaphthyl alkyl 1 piperidylsulfonylbenzoates. More specifically, this invention relates to optically active 4,4a,5,8 tetrahydro 2 alkoxy-amethyl--oxo-l-naphthyl alkyl l piperidylsulfonylbenzoates having the formula wherein R1 and R2 represent alkyl radicals containing from 1 to 5 carbon atoms, and to a method for their preparation. The letter s in the structural formula indicates a saturated ring structure.

The novel compounds of this invention are exceptionally useful intermediates for the preparation of various organic compounds, particularly pharmaceuticals. These esters are exceptionally useful intermediates for the preparation of steroids. They may be conveniently prepared by reacting an optically active alkyl-l-piperidylsulfonylbenzoyl halide, wherein the alkyl group contains from 1 to 5 carbon atoms and a 5,8-dihydro 4 hydroxy 3 alkoxy 8a methyl-1- (8aI-I) -naphthalenone, alkali metal or alkaline earth metal salt, wherein the alkoXy group contains from 1 to 5 carbon atoms. These latter salts may be represented by the following formula s I 7 R30 34/423 6 wherein R represents an alkyl radical containing from 1 to 5 carbon atoms and X represents an alkali metal or an alkaline earth metal. It will be obvious to those skilled in the art that the 5,8-dihydro 4: hydroxy 3 alkoxy-8a-methyl- 1 (8aH) -naphthalenone, alkali metal and alkaline earth metal salts, contain an asymmetric carbon atom. As a result thereof, the compounds exist in two optically active forms, namely, the dextrorotary (d) and levo-rotary (Z), and both forms and mixtures thereof are contemplated by this invention and may be utilized to prepare the correspondingly optically active esters of this invention. v

' Similarly, the 2-alkyl-l-piperidylsulfonylben- Example I 5.70 g. of til-5,8-dihydro-4-hydroxy-3-methoxy 8a-methyl-1(8aI-l) -naphthalenone, sodium salt, is suspended in ml. of dry dioxane at 100 C. 7.54 g. of d-p- (2-methyl-l-piperidylsulfonyl)benzoyl chloride is added and the suspension rcfluxed for about five minutes. About 70 ml. of dioxane is then distilled from the reaction mixture under reduced pressure and the residue remaining poured into 250 ml. of water, thereby precipitating the solid ester. The solid ester is recovered, dried immediately, and purified by recrystallizing once from a mixture of acetone and diisopropyl ether, giving a substantially pure mixture of diastereoisomeric 4,4a,5,8-tetrahydro-2- methoxy-4a-methyl 4 oxo 1 naphthy1p-(2- methyl-1-piperidylsulfonyl)benzoate esters having the following analysis:

Melting point about -181" C.

Optical rotation [a] =+19-* -1 (c=2, chloroform) Sulfur Calculated for CZEHZQOBNS 6.30 6.90

Found Example II In accordance with the procedure described in Example I, substantially pure 4,4a,5,8-tetrahydro- 2-ethoxy-4a-methyl 4 oxo 1 naphthyl o-(3- ethyl 1 piperidylsulfonyl)benzoate is obtained utilizing the following reactants:

6.46 g. of dl-5,8-dihydro-4-hydroxy-3-ethoxy-8amethyl-1(8aH) -naphthalenone, potassium salt 7.54 g. of Z-o-(S-ethyl-l-piperidylsulfonyl)benzoyl chloride Example III 3 is then distilled from the reaction mixture under reduced pressure and the residue remaining poured into 250 ml. of water, thereby precipitating the solid ester. The solid ester is recovered, dried immediately, and purified by recrystallizing once from a mixture of acetone and diisopropyl ether, giving a'substantia l'lymure mixture of diastereoisomeric 4,4a-,5;8-tetrahydro-2-methoxy-4a-niethyl-4-oxo-l-naphthyl p-(2-methyl-1-piperidylsulfonyDbenzoate esters having the following prop-' erties:

Melting point, 175-181 C. Optical rotation [l =-'193 '-:1"'

form) Example IV In accordance with the procedure descrih'edz in Example I, substantially pure 4,4a,5,8-.tetrahydro- 2-pentoxy-4a-methyl 4- oxo-l-napli'tliylm lpropyl l piperidylsulfonyl(benzoate is obtained utilizing the following-reactants 7.04 .g. ofl-5,8-dihydro4Phydroxyr3,apentoxy.-8amethyl- 11(81aH) -naphthalenone, calcium-salt 9.36 .g. of..m-(4epropyl-1=piperidy1sulionyl) ben .,.zoyl bromide Example V In accordance :withthe procedure described in Example 21,. substantiallyiipure 4,'4a,5,8-itetr'a hydrd-2=ethoxy- 4a'-unethyI-4=oxo-1=naphtliyl p'=(2- methyl-l-piperidylsulionyltbenzoate is obtained utilizing. the. iollowing reactants:

.6.D5.;g ..ofiirlh5,8a-xiihydroeeehydroxy-fil-ethoxyi-8a methyl.-118aH)1-naphthalenone,=sodium salt 7:54 g.iot cl pi2emethyl-l'piperidylsultonyl) ben- :1 zoyl ich-lori'de 'Exam'plevl In. accordance with the procedure: describedl in Example. Lnsubs-tantiailyi pure .4; la,5;8- tetrahy riro -& :2r-pnopoxywia-methyl-4-1oxo+1 -n aphthyl 1-p- ..(2 methyl -.,-1 piperidylsulienyl)Fbenzoate -iswob- :tained.utilizingstheetollowing:reactants 6.41 g; i of dl5;8"-dihydro-4 hydroxy-3-propoxy- -'Sa methyI-1(-8aH) naphthalenone, sodiumsalt 7-.54' grbf d-p'=iZ-methyl 1=piperidylsulfonylThen- I zoyi chloride Example VII .In-accordance-with: the procedure :describedtin Example I, substantially pure 4,4a,5,8-=tetr.ahydro-2-butoxy-4a-methyl-4-oxo-l-naphthyl p-(2- methyl-l-piperidylsulfonyl) benzoateis obtained 'ut'rlizingthefollowing reactants:

6.76 g. of dl-5,8-dihydro-4-hydroxy-3-butoxy-8amethyl-1(8aH) -naplithalenone, sodium salt 7 .54 g. of cl-p- ..(2emethyl--1-piperidylsulfonvl)benzoyl chloride Example VIII In accordance with. the .proceduresdescribed-in Example I, substantially pure 4,4a,5,8-tetrahy- 'dro -'az-pentoxy iasmethyl 4-oxd-l=naphthyhp- (2 methyl -l-piperidylsulfonyllb'enzo'ate is ob- -tainedi utilizing 1 the-:following-react ants 7.12 g. of dZ-5,8-dihydro-4-hydroxy-3-pentoxy- 8a-methyl-1(8al-D -naphthalenone, sodium salt 7.54 .g.,.ot d-p-m emethylq epiperidylsulionylrbem zoyLchloride Whilethe preceding" examples-haveillustra ted specific embodiments of this invention; substanlti'al" .variationuismos'siblein' thevquantities fbi reactants, reaction conditions, etc., without departing from the scope of this invention. For example, while approximately equivalent proportions of the reactants are preferred, an excess of either 5 of these reactants may be utilized, if desired.

The reaction may be carried out in any inert rea'ction medium. Forexample, the reaction may sbecarried'out in.dioxane, lower alkyliethers, benzene, toluene, xylenes, etc.

50 7 The reaction may also be carried out over a v..substantial temperature range. Reaction temp'eratures' ranging -from the freezing point of the reactiom'mixtu-reto the boiling point of the reacitiorrzmixturamayme utilized. Preferably, the rel5sactionfiisi carried out at a temperature in the range of from about C. to about 110 C.

.':The 5,8 dihydro-4-hydroxy-3-alkoxy-8a-meth yl-1(8aH) -naphthalenone, alkali metal and ali kaline 'earth metal salts, utilized in this invention are described and iclaimed in my copending application- Serial --No. 253554; filed. Octoberr27, .I951. ...The optically. active 1(alkyl-1-piper-idylsulion-yllbenzoyl halides utilized .in this invention areadescribedandrclaimed. in my". ioopendingaapplication x-Se1dal -No..;260,568,,:filed.December 7,

What is claimed-is: 1. As new chemical compounds, optically active 4,4a,5,8 tetrahydro 2 -1 alkoxy 4a methyl 4- 0x0 1.-naphthyl.alkylelepiperidylsulionyl-benzoates having the formula wherein R1 and R2 represent alkyl radicals con- -ta-iningairom 1 .to 5 carbon atoms :andwhereinathe .aliayl-lrpiperidylsulfonyl radical-is -se1ected.:from .the: \group' ..consistingof 2-.allcyll-piperidylsul- .fonyl. and en-alkyl-l+piperidylsulfony1 a radicals. .2.- As. a new chemicalseompoundrgoptically 'acitiver;4,4a,5,8 -.ztetrahydro-2+methoxy-4a;-methylwherein R1 'and Rs'represent alkyl radicals 10013- taining from 1 to 5 carbon atoms and "wherein the alkyl-l-piperidylsulfonyl radical is selected from the group consisting of 2-alkyl-1-piperidylsulfonyl and 3-alky1-1-piperidylsulfonyl radicals, which comprises reacting a compound selected from the group consisting of 5,8-dihydro-4-hydroxy 3-alkoxy-8a-methyl-1(8aH)-naphthale none, alkali metal and alkaline earth metal salts, wherein the alkoxy group contains from 1 to 5 carbon atoms, and an optically active alkyl-1- piperidylsulfonylbenzoyl halide selected from the group consisting of 2-alkyl-l-piperidylsulfonylbenzoyl halides and 3-alkyl-1-piperidylsulfonylbenzoyl halides, wherein the alkyl group contains from 1 to 5 carbon atoms.

8. A process for the preparation of optically active 4,4a, 5, 8-tetrahydro-2-methoxy-4a-methyl-4-oxo-1-naphthyl p-(2-methy1 1 piperidylsulfonybbenzoate, which comprises reacting 5,8- dihydro 4 hydroxy 3 methoxy-8a-methyl- 1 (8aH) -naphthalenone, sodium salt, and optically active p-(2 methyl-l-piperidylsulfonyl)benzoyl chloride.

9. A process for the preparation of optically active 4,4a,5,8 tetrahydro-Z-ethoxy-4a-methyl- 4 OX0 1 naphthyl p-(2 methyl-l-piperidylsulfonyDbenzoate, which comprises reacting 5,8- dihydro 4 hydroxy 3 ethoxy 8a methyl- 1(8aH) -naphthalenone, sodium salt, and optically active p-(2 methyl-l-piperidylsulfonyl)benzoyl chloride.

10. A process for the preparation of optically active 4,4a,5,8 tetrahydro 2 propoxy 4a- 6 methyl 4 oxo 1 naphthyl p (2 methyll-piperidylsulfonyl)benzoate, which comprises reacting 5,8 dihydro 4 hydroxy 3 propoxy- 8a-methyl-1(8aI-I)-naphthalenone, sodium salt, and optically active p-(2 methyl 1 piperidylsulfonyl) benzoyl chloride.

11. A process for the preparation of optically active 4,4a,5,8 tetrahydro 2 butoxy 4amethyl 4 oxo 1 naphthyl p-(2 methyl-1- piperidylsulfonyl)benzoate, which comprises reacting 5,8 dihydro 4 hydroxy 3 butoxy- 8a methyl 1(8aH) naphthalenone, sodium salt, and optically active p-(2-methyl-1-piperidylsulfonyl) benzoyl chloride.

12. A process for the preparation of optically active 4,4a,5,8 tetrahydro 2 pentoxy 4amethyl 4 oxo 1 naphthyl p-(2 methyl 1- piperidylsulfonyl)benzoate, which comprises reacting 5,8 dihydro 4 hydroxy 3 pentoxy- 8a methyl 1(8aH) naphthalenone, sodium salt, and optically active p-(Z-methyl-l-piperidylsulfonyl) benzoyl chloride.

QUENTIN E. THOMPSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,506,023 Jenny et al. May 2, 1950 2,506,024 Jenny et a1 May 2, 1950 2,506,025 Jenny et al. May 2, 1950 

1. AS NEW CHEMICAL COMPOUNDS, OPTICALLY ACTIVE 4,4A,5,8 - TETRAHYDRO - 2 - ALKOXY - 4A - METHLY - 4OXO - 1 -NAPHTHYL ALKYL-1-PIPERIDYLSULFONYL-BENZOATES HAVING THE FORMULA 